RecruitingBehavioural interventionThe Influence of Aerobic Exercise on Consolidation of Fear Extinction Learning in PTSDThis study aims to test whether aerobic exercise performed after fear extinction learning improves cognitive, physiological, and neural indices of extinction recall in a sample of trauma-exposed men and women with and without posttraumatic stress disorder (PTSD). Participants will complete a clinical intake visit (Day 0), followed by a three-day fear conditioning (day 1), fear extinction + activity (day 2), and fear extinction recall (day 3) protocol.